MOM1 IS A SEMI-DOMINANT MODIFIER OF INTESTINAL ADENOMA SIZE AND MULTIPLICITY IN MIN + MICE/

The intestinal tumor multiplicity in mice heterozygous for APc(Min) is strongly modulated by genetic background. On the sensitive C57BL/6J ( B6) background, mice develop large numbers of intestinal adenomas. The AKR/J (AKR) strain carries alleles that correlate with a strong reduc tion in tumor multiplicity. To study the effect of one of these modifi ers, it Mom1, we have generated a mouse line in which the AKR allele o f Mom1 is carried on the sensitive B6 genetic background. This strain was produced by using a marker-assisted selection method to eliminate unlinked AKR alleles more rapidly. The application and efficiency of t his method are discussed. We used this strain to determine that Mom1 a ffects both tumor multiplicity and tumor size in a semi-dominant fashi on.